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    <title>Document</title>
    <script type="text/javascript">
        var year = parseInt(prompt("请输入任意年份"));
        if ((year % 4 == 0 && year % 100 != 0) || year % 400 == 0) {
            alert(year + "年是闰年")
        } else {
            alert(year + "年是平年")
        }
    </script>
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